MasterCard has revealed plans to support in-app payments via its virtual online wallet payment system, MasterPass, in response to the growing potential of mobile payments.

MasterPass lets users store all their payment, store card, loyalty, shipping and billing address details in one place and pay for goods and services online from retailers that have signed up to support the wallet. Previously it was only browser-based, but MasterCard has announced plans to integrate it into mobile apps — it will be made available to developers and merchants starting in the second quarter of this year.

This means that apps with MasterPass embedded in them will enable consumers to complete a purchase without having to leave the app at all. It also eliminates the need to store payment card credentials across various mobile apps — as MasterPass will provide the details needed to facilitate a transaction.

The service requires an integration “similar to the process for online merchants” – which means retailers have the opportunity to add more payment options to streamline their checkout experience.

MasterCard cites ABI Research as saying that overall revenues from mobile apps, which includes in-app purchases, will reach $46 billion by 2016, over five times more than the $8.5 billion recorded in 2011 — which is little wonder that it wants to plunge deeper into this space.

In its push to develop mobile payments further, MasterCard also announced at Mobile World Congress in Barcelona today that it is acquiring C-SAM, a provider of mobile and digital wallet services. Terms of the deal were undisclosed, but it is clear that C-SAM’s back-end infrastructure will help boost MasterCard’s push for its MasterPass service.

“In acquiring C-SAM, MasterCard will speed the development and deployment of mobile wallets and payment solutions globally, including the rollout of its MasterPass digital service,” the credit card company says in a statement.